Chelsea midfielder Jacob Mellis has left the club "by mutual consent" after he admitted setting off a smoke grenade at their training ground.

The Blues confirmed today they and 21-year-old Mellis, who has played for the first team, had "parted company" following a "full and thorough" investigation into the incident which took place on March 2.

Team-mate Billy Clifford escaped with a fine after admitting he brought the grenade - understood to be from a paintball expedition - into Chelsea's Cobham training headquarters.

Clifford, 19, is a regular in Chelsea's reserves and signed a new four-year deal last summer.

Mellis, 21, joined the Blues from Sheffield United five years ago and made his debut in the Champions League win against Zilina in November 2010.

According to reports, the smoke grenade was set off in the reserve-team dressing room and trained fire marshals had to be brought in.

Players, officials and other staff from Chelsea's reserve, youth and academy teams ran from the building with hands covering their faces because of the thick smoke.

Owner Roman Abramovich was reportedly briefed about the incident, which occurred shortly before training at 10.30am and set off fire alarms and triggered a full evacuation procedure.

It was also the latest controversial episode to occur at Chelsea's training ground.

Last February, defender Ashley Cole accidentally shot and wounded a work experience student with an air rifle.

It is believed Cole did not know the rifle was loaded and he apologised to the student, who did not require hospital treatment.

And, late last year, a knife was discovered by cleaning staff in a dressing room at the complex, although this was thought to have belonged to a building contractor on the site.